Gents,

I've searched here and got some answers but still need more.

Scenario, 98.5 replaced stock batts quite awhile ago with run-of-the-mill maintenance free which puked all over the place and after 2 yrs were replaced with red tops.

Loved the red tops but killed them with an overcharge after accidental discharge (left lights on) with a manual charger.

Replaced those with full maintenance non-brand less than a year ago. Somewhere between the red tops and the latest replacement I rebuilt the alternator after it failed. It was obvious, low volts. Sometimes volts would stay low then perk up to 14.3 then die again.

Since the rebuild, I've always had 14-14.3v at the batts while running.

These days, with a little chill in the air and the truck sitting a couple of days I have dead batts. After sitting I have 11.8v which would signify these are pooched.

If I always have 14+v while running why did they go south? I mentioned these were full maintenance. The electrolyte is always up. Could there be a current (amperage) issue with the charging system? How do I check to make absolutely sure? Is saying I have 14+v proof enough?

I'd like to go back on warranty with these batteries since we all know only one cell has to fail to take both batteries out.

Appreciate any insight on this.

Cheers,

Taz

 

check all your connections and pull your positive battery cable and do a continuity test between that and your frame or a good ground if you get continuity it sux but you could have a short somewhere that you need to find that will cause a fluctuation with your alternator and can kill your alternator and it will drain your batteries

 

I agree with the above. Are all of your contacts and ground connections clean? You would be surprised at how corrosion will eat away at your charging system and voltage, giving the PCM all kinds of incorrect data and passing this 'misinformation' on to the poor alternator, which doesn't know when to or how much charging your batterys truly need.

 

So....then what I'm hearing is it doesn't really matter that I have 14+v consistently.

If connections or cables are funky, this will throw the ECM off and give incorrect info the alt.

Clarification/addition anyone??

Taz

 

Pull the batteries and have them load tested. Thats the best way to determine that they are good.

 

13.8 to 14.2 volts is usually the specification for a running vehicle. What you are asking is should it be 11.8v. after sitting for a day or two? If that is what you are asking, the answer is no!

You could again have weak batteries or you could have a draw on the electrical syst. which in turn is draining your batteries down after a few days.

Two ideas have been mentioned already: the fist was having the batteries checked at a battery/parts store.
The second was to check you electrical syst. for a drain/draw. To do that you have to completely disconnect one battery and then take the battery you still have hooked up and disconnect it, then take a test lightand hook it in between the cable you disconnected on the last battery. (you should really use an ammeter in line if you had one, but you need to be carefull doing the ammeter). If you have a draw on the syst. the test light will light. It could be very very dim (if you are lucky) or it could be close to normal brightness (meaning you have quite a draw on the syst.)

The next step in the process is to try to figure out where the draw is: If the light was quite bright, I would first disconnect the connections to the alternator and see if the light goes out or gets dimmer. If it does not change the brightness than the alt. is OK. Leave the alt. disconnected and then start pulling fuses and relays one at a time while watching the test light for brightness.

In this computer age, you will never get the draw to completely go away, because of all the computers, Examples such as: ABS / Eng. Ecu / Stereo memory / body ECM and so on! These all have memories that will draw very minimal amps. as long as thay are working correctly.

Good luck.